Controllable Low Proton Source

1. A controllable source of few photons of predetermined wavelength, the source being characterized in that it comprises a solid material ( 10 ) having a dilute concentration of elements ( 11 ) implanted therein that emit light at said predetermined wavelength, an excitation device ( 20 ) for exciting said light-emitting elements, and a probe ( 30 ) suitable for capturing, by near field coupling, at least one photon emitted by one of the light-emitting elements.

2. A source according to claim 1 , characterized in that the concentration per unit area of the light-emitting element in the solid material is fewer than 10 per m 2 .

3. A source according to claim 2 , characterized in that the concentration per unit area is fewer than 1 per m 2 for a single-photon source.

4. A source according to claim 1 , characterized in that the photon captured by said probe ( 30 ) is emitted into free space.

5. A source according to claim 1 , characterized in that an optical fiber ( 40 ) is coupled to said probe ( 30 ) to transport the captured photon.

6. A source according to claim 1 , characterized in that said light-emitting element is a rare-earth ion.

7. A source according to claim 6 , characterized in that said rare earth ion is selected from the list constituted by: erbium, praseodymium, neodymium, and ytterbium.

8. A source according to claim 1 , characterized in that said light-emitting element is uranium.

9. A source according to claim 1 , characterized in that said light-emitting element is an organic molecule.

10. A source according to claim 1 , characterized in that said solid material ( 10 ) is an electrical insulator.

11. A source according to claim 10 , characterized in that said electrical insulator is selected from the list constituted by: silica, alumina, a nitride, a polymer, a glass, a fluorine-containing crystal, and a sol-gel.

12. A source according to claim 1 , characterized in that said solid material ( 10 ) is a semiconductor.

13. A source according to claim 12 , characterized in that said semiconductor is selected from the list constituted by: amorphous silicon, polycrystalline silicon, and GaN, GaAs, GaP, GaSb, InP, and derivatives thereof.

14. A source according to claim 1 , characterized in that it includes means for controlling the capture of the emitted photon by the probe ( 30 ).

15. A source according to claim 14 , characterized in that said control means are means for controlling the distance between the probe ( 30 ) and the light-emitting element.

16. A source according to claim 1 , characterized in that said probe ( 30 ) is formed by a tapering point ( 31 ) of size smaller than 1 m.

17. A source according to claim 16 , characterized in that said tapering point ( 31 ) is made of a material that is dielectric or semiconductive.

18. A source according to claim 16 , characterized in that said tapering point ( 31 ) is made of carbon or of silicon.

19. A source according to claim 16 , characterized in that said tapering tip ( 31 ) is constituted by the end of an optical fiber.